Não informado. (1972). Alternative sources of energy. Alternative Sources of Energy.
Chicago-referens (17:e uppl.)Não informado. Alternative Sources of Energy. Milaca, Minn: Alternative Sources of Energy, 1972.
MLA-referens (8:e uppl.)Não informado. Alternative Sources of Energy. Alternative Sources of Energy, 1972.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.